Negative pressure wound therapy (“NPWT”) systems are used to accelerate wound healing by applying a negative pressure to a wound. Generally, a NPWT system covers the wound with a flexible cover layer such as a polymeric film to establish a vacuum reservoir over the wound where a negative pressure may be applied. To allow the negative pressure to be maintained over time, the cover layer may include an adhesive property that forms a substantially fluid tight seal with the skin surrounding the wound. Most NPWT systems apply a negative pressure to the wound using an external vacuum source such that fluid communication must be established between the reservoir and the vacuum source. To this end, a fluid port is coupled to the cover layer to provide an interface for an exudate tube extending from the external vacuum source.
While such systems can accelerate wound healing, they tend to suffer from a number of drawbacks, especially for patients with lower limb injuries, such as pressure ulcers, surgical cuts/incisions, or amputations. For instance, known systems are often bulky and heavy, especially for use after a patient has been discharged from a hospital. Furthermore, these systems typically include an external vacuum source intended to be worn close the patient's waist, necessitating routing of the tube from the waist to the wound area on the lower limb. The tube can then become tangled or caught during use, disabling the NPWT system and/or injuring the patient.
The height of the vacuum source above the wound area also generates a fluid head height tending to act against the negative pressure applied at the wound area. In addition, movement of the patient's foot relative to the location of the system on the patient's waist can drastically vary the fluid head height, which, in turn, can vary the level of negative pressure applied at the wound area, producing unpredictable and even damaging effects.